Method of and apparatus for introducing grout into subsoil



July 9,`19.46. 'A G. L; DREssER METHOD OF AND APPARATUS FOR INTRODUCING GROUT INTO SUBSOIL Filed Feb( 25, 1944 2 Sheets-sheet 1.

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Patented July 9, 1946 S PATE 2,403,643 i Y Y f NT-FF1CE n METHOD or AND APPARATUS Fort INTRO-V nUcmG GnoUT m'rosusom George L. Dresser, Albany,l N. Y. c I' Application February 25, 1944, 'serial 10.523,946

The present invention relates to methods of and apparatus for introducing grout or the like into subsoil either for the purpose of `increasing its bearing strengthor to rprovide an anchoring massfor a pile. d

y More particularly stated the invention pertains to.. a Ynovel method and apparatus by means of which grout, or other material of generally similar nature, which has lthe capacity to harden or solidify from a plastic conditionsmay be convenientlyintroduced intoy permeable subwsoil of sandy or gravelly nature for the purpose of firmly supporting the lower end of a pile or lforincreasing the bearing strength of such soil, or al body of such material established at a desired distance below4 the surface of a bed of `dense soil, such as clay, such body forming the anchoring means for a metallic pile or column the upper end of which may project above the surface of the ground. The method and means of the present invention are of such nature that an adequate foundation for any structure however massive,`may be readily established at almost any site, even though soil conditions are most unfavorable. The invention is highly useful in ,establishing adequate foundations for new buildings and is likewisev of great value in strengthening foundations of structures previously erected. While, in establishing the foundations for buildings to be newly erectedit is quite possible to use conventional piling, in the event that the soil is of low bearing strength, it is not alwaysy possible to use conventional piling in the reinforcement of the weakened foundations ofstructures already erected, the weakened foundations of such structures being quite often unable to withstand the vibration or shock incident to the placement of piling by mechanical driving methods.

In the event that a body of permeable subsoil is to; be treated in order that its bearing strength may be increased this may be readily accomplished, in accordance with the present invention, by causing a jet or jets of a washing liquid such Y f 2; 4 below the surface has been cleared of its least desirable constituents. The flow of wash water may vthen be discontinued and vgrout under ypressure treated and a soil of limited bearing strength con-f verted, in place, into a solid or body of great bearing strength, in a rapid, economical manner. By

causing the washing operation to be carried out over a considerable area, measured horizontally, and by washing both deeply and toward the surface, a very large body of y permeable soil may be treated and its bearing strengthincreased, vthe washingandgrouting operation being carriedjout over; as wide an area, and as deeply, as maybe deemed necessary. The permeable *soily beneath d existingVv structures may be treated in this mane as water to be delivered`Y` into the body of per-v Y meable soil at a selected point below the surface and the washing effect of a owing stream utilized to remove from the permeable body a substantial proportion of its lighter and weaker elements, leaving the denser and, stronger elements such as stones behind, the wash water with its suspended waste matter being brought to the surface, bysuction means if desired, and disposed of. The washing is continued until it is perceived, by inspecting the wash liquid which reaches the surface, that at leasta substantialbody of the permeable material ner and the structures thus strengthened or, as has been `previously stated, the grouting may beV employed as a step preliminary to the erection of a new structure. c Y

In dense, hard soil, which ordinarily provides adequate support for building structures, it is nevertheless frequently desirable to establish piles the upper ends of which project above the ground level, vand Ywhichvmay constitute supporting or anchoring elements which may neither be with:- drawn from the ground or forced downwardly by pressure. In accordance with the invention av body of'groutor concrete may be readily established `.inv subsoilof dense or clayey nature, to serve vas a submerged anchor for a pile, or forr anyother purpose, all without the aid of vibration'` or shock creating instrumentalities. A Hence if, for

' any reason. it is necessary to introduce a body of grout orconcrete into the earth near anCXSting structure this may be readily yaccomplished with` out danger to such structure. In placing and anchoring apile in dense soil a, combinedrpile and jetting-or earth penetrating device is Vintroduced intothe earth by the action of a jet of Wash liquid unclerpressurey which issues from the end of the devicefandA a shaft' belngthus created as the device moves. ,dcwnwardlm the downward rnvementl f When the grout hardens the zone into which it has been introduced becomes a solid massA being halted only after it has penetrated the desired distance. The washing action of the jet is, however, continued after its downward movement has ceased for the purpose of dislodging and bringing to the surface a body of the dense subsoil and thus creating at the bottom of the shaft a considerable cavity in the earth.

Suction means may be employed to Withdraw the wash waterfrom the earth and, inany event, the washing out action will be continued until it is estimated, by observing the character and exe y conduit for leading wash water with its suspended tent of the solids withdrawn, that a cavity of de- 'A 2 -of the drawings.v It comprises essentially a sired size has been formed. The how 'of wash water is then interrupted and grout forced-"clown-` wardly through the jetting device,v -whichr .l also serves as a grout conduit, until the grout completely iills the cavity formed `bythe eroding acl tion of the stream of wash water, a substantial body of articial stone or the like resulting'. TheM jetting or earth penetrating device is allowed to remain while the body 'of lgrclut'V is harden-ing so that, when the grout has hardened, thejetting device isrmly bound and may lnot be moved. Its upper Vend Imay `project "above the ground andbe employed as a` stable-point `forthe attachment of any structure vto 'be securedagainst 'movement' in any direction.

'Cine apparatus is Vemployed for carrying out either method andone VformV of this app-aratusis illustrated; by wayy oexample, in theaccompanying ldrawings in which,"

:Figure 1 is a Side view of the elongated element for-sinkingl the necessary Ishaft,--and transmitting wash water and grout intolthe subsoil;

` vFigure 2 yis an axial 'section thru this element, partly ;broken away in 4order that the remainder may'be'shown ona largerscale;

' A"Figure 3- is a diagrammatic view showing, in verticalsection, `a body of subsoil into which 'grout' is-to be introduced, Ytogether with the various essential pumps, etc.A Aof the yimproved 'apparatus grouped together upon `the surface;

'Figure 4 is -a top` pla-n View of the apparatus shown i-nFigure 3;v f

l Figures' to 9, inclusive, are of diagrammatic nature-and successively indicate the various -positions -ofthe jetting or earth-penetrating element offthewash liquid land g-rout-transmitting apparatusas used AinA the treatment of a body -of permeablesoil, such aslg-ravel, to give itincreased bea-ring strength;

Figures to 14, inclusive, are also matic nature and show, in sequence, the several steps involved in the establishmentof -a pile in a body ,of .Clayey soL 'The apparatus includes the elongated earth penetrating device villustrated in'Figures 1 and 2, by lmeansof which wash water and grout may be introduced into -thesubsoil, together with suitable vmeans such as indicated `in Figures 3 and 4 for providing a supply of water -underpressura air under pressure, and grout under pressure, to gether with a suction pump. A settling basin or reservoir for the reception of washr liquid which issues from the earth after having been utilized for'soil washing -or excavating purposes is also preferably utilized, In Figures 3 and lithe elongated earth penetratingelement is indicated at IiU, Va water pump by meansof which water under pressures vup to 300 pounds Yper square `inch canv be supplied, is indicated at II, a compressor vfor air is indicated at I2, a suction pump at I3, a

grout pumpat I4, and a reservoir for receiving wash water and washed out solids at Rl Suitable flexible conduits connecting the water' and air of diagram# the soil may most readily be perceived in Figure 'tubular cas-ing Y2li which may be relatively long v in the -event that deep soil penetration is desired or' relatively short when shallow penetration only i-isnecessary. `Disposed within and coaxial with thecasing 20 is a pipe or conduit 2l. The lower end ofthe casing 2!) is connected to a cast steel tip 22 and the lower endof the pipe or conduit 2| is likewise connected-to this tip. The lower end of the casing is received within the upper-.end 4of a sleeve 23 which -sleeve is in the nature of a short standard coupling, thelower end of this coupling projecting into a downwardly tapering recess 22a, formed in the rearend--of the tip 22, in which position it is permanently secured as by a weld 274. Due to the fact that the recess 22 tapers downwardly, as stated', there willbe no difculty in assembly :despite minor variations in coupling diameter. Thefinner face-of the sleeve 23, at the upperend thereof, -is interiorly threaded and this thread receivesa corresponding thread formed upon the outer surfaceof the lower end of the casingZ. The :inner-pipe orffconduit 21|- likewise projects, 'at its lower lend, into the upper end of a sleeve or-standard coupling member 25,

recessZZa-which recel-ves sleeve23,-sleeve 25 being` likewise permanently Aattached to the tip- `by means oftheweld 2S. .A-jcentral channel through the tip 22 is indicated -at 21 thiscentral channel terminating vvin` a port 28 yformedy in `an earthengaging outer surface Aof the tip, 'at the smaller endY ori-point thereof; Preferably this eartheng-aging outer surface'is lfrusto-conica-l -as 'shown and the -tip may advantageously be fabricated of cast steel. The wash liquid to be used in sinking the earth-penetrating element, or to be introduced into the body-of earth'to be excavated or washed, passes downwardly through pipeZI and issues as a jet from port 28. l Y

-I-t will be observed that the casing 20 has -a short upper section 2l)a which is connected to the lower section by lmeans of a If-member A3l! having a laterally extending branch 30a. Liquid issuing from'branch 30a-of the lf-member passes thru fa nipple -I-PI and then thru the -casing of a valve V. The valve V may-'beef any suitable type provided that it vmaybe adjusted to interrupt or perm-it, as desired, yflow of liquid from the casing 2i! to the offtake tube -34, '-to which tube the vinlet end ofa exible hose or conduit, such as indicated at I1 in Figures `3 and 4, maybe attached.

The inner duct or vconduit v'2-I` projects upwardly beyond the upper end of the upper portion 20B of the casing and this projecting portion is encircled by annular vflanged caps 35 and 31. The

andithe 'downturned flange rof the -cap '3l has threaded engagement with the'outersurface' of the upper end of a tube or sleeve 38 welded, as;

sleeve v38 there is contained a body 4|]4 of packing material.. This packing materialprevents, when placed under pressure by suitably adjusting the` position of capf31, leakage from thecasing 20 upwardly past cap 36 aroundvthe outside of the pipe or conduit 2|. The upper end of pipe 2'I projects into the lower end of a T-member .4| and, into the upper end of this T-member, there projects a nipple 42 to. which is connected a valve casing` 43. The movements of thevalve within the casing are controlled by handwheel 44. A taperednipple 45 is Aconnected tothe upper end of the valve body and to this nipple may be connected the end of a flexible hose for the transmission, from` a vsuitable source of supply, of a compressed gas such-as compressed air.

vThe lateralbranch 4|a.ofthe T-member 4| is connected by means of a nipple 46 to the outlet end of a valve body 41 which valve body is likewise `provided Vwith a. valve the movements of which are controlled by a handwheel 48 and with an inlet'nipple 49 which maybe connected by means ofa flexible hose toy asuitable source of wash liquid under pressure. As shown in Figures 3 and`4 the nipple 45 is connected to the air hose |6,the nipple '49 to the hose |5 leading from the water pump and the nipple 34 to the discharge conduit or hose |1.

` The lower end of the casing 28 has formed therein a plurality of relatively small apertures or ports 2|!b which areprovided to permit Wash liquid which has been discharged through the 'port 28, and has moved'upwardly, to re-enter outwardly through theA nipple 3|, valve V, nipple 34 and offtakefconduit |1 to a point where it may be wasted or collected in a pond or settling basin such as that indicated diagrammatically at R. Thevwash water entering the soil penetrating element,v of course, `passes through valve body 41 and downwardly through pipe 2|.' During thel washing operation the valve controllingv the flow of compressed air into pipe 2| will normally be in closed position. If at any time, however, it isv desired toproject a stream of air under pressure into the subsoil the valve within casing 41 will be closed and lthat within valve casing 43 opened. Hence the element l may be employed either to project a stream of wash water into a body of soil, or a current of compressed air or, in some cases, both wash water and compressed air, for purposes hereafter to be mademore clear.

Two preferred methods of use of the apparatus as so far described may be most readily perceived from an inspection of Figures 5 to 14, inclusive. Where it is' desired to increase the load bearing strength of a body of Vpermeable soil the 'appaatus is moved into position and the soil penetrating element 0 disposed vertically just above the zone or body which is to be strengthened with grout, the apparatus being shown in this initial position in Figure 3.' Handle 48 is then manipulated v'to open the associated valve and permit the inflow of water under pressure into the inner duct 2|. The jet of water will be projected from the tip 22, through'fluid discharge port 28, against the? surface"` of 'the ground. 'Due to the eroding effect of the water jet the soil immediately below the cast steel tip 22 will be displaced and the' element `||l will begin to settle into the ground,

vduring this preliminary stage the wash water simply passingupwardly around the outer surface ofthe tip 22 and flowing away over. the surface-v of the ground. The action of the jet is continued and the downward movement of the elementY I0 likewise continues, the downward` movement being aided somewhat by pressure from above if necessary.

j After the elementl |0 has sunk part way toward its final position, t0 such rextent that the aper;

lift applied to the column'of outflowing'wash-v water.l .Theraction may be continued Auntil the element-lll has penetrated `into the permeable soil tothe desired extent, for instance to the p'osi' tion diagrammatically illustrated in Figure 6. The vflow of wash water ymay be continuedY after full penetration has been obtained, however, in

order .that 'further washing of the permeable body of earth around the lower end of element ID' may be effected, preferably at reduced pressure. If desired, the ow of water may'bevdiscontinued and air under pressure allowed to flow to the dischargeport 28 of the tip and thence into the surrounding soil, to further prepare the soil for the grout which is to follow, or air and water allowed to flow together to and out of port 28. I l l V Afterv such washing' has -been l'completed T`- member 30and associated partsare removed fromL the upper end of the casing 2|), the lower end of pipe 2| being unscrewed from the coupling member y25 and the pipe 2| with caps 36-and` 31,*and parts 38l and2llaL lifted upwardly. A further cap.'- indicated diagrammatically at 50, is then affixed to the upper end of casing 20, this cap having connected'theretol the end of a flexible duct orv hose 5| leading to the delivery port of the grout pump diagrammatically indicated at |4.V The pump is then operated to deliver grout under substantial pressure tothe casing 20, the grout passing downwardly through the casing and outwardly through the discharge port 28 and through the ports 2|)b formed in the casing and which have previously been employed as Water inlet ports.

body of `soil surrounding the lower end of element I0 at higher elevation, the element I0 being halted from time to time in its upward movement, one such more elevated grout delivery point bein-g indicated in Figure 8. Figure 9 illustratesl diagrammatically' a body of earth into which.A

ennemis" grout has been forced from a point well below the surface .allthe way up to the surface so that this body lhas been transformed into a relatively deep body 'of concrete, in place, the aggregate .having been present originally and having been washed, in place, to eliminate its Vmore `undesirable constituents and to make room .for the grout which forms the matrix for the concrete. While this method .is particularly useful where the lsubsoil contains many stones and rocks it is nevertheless useful even where the subsoil contains large quantities of vegetable matter. Washing v'operations may be conducted from points closely adjacent the surface to `points far below the surface :and

grout injected under heavy pressure to fill the voids created and to force its way into and through the interstices of the earth. 4Any character of subsoil, however poor, can be given greatly increased bearing strength by the method of grout application which has just been described. If itis desired to establish a permanent pile instead of simply increasing the bearing strength of the porous soil, and it is frequently so desired, the pumping of grout may be halted when a sufficiently large anchoring body has been established, such for instance as indicated in Figure '-7. The casing 20 and tip 22 are left in place, the pump disconnected, and-a suitable cap placed upon the upper end of the casing, if desired.

Where the soil is dense vand particularly where it is desired to restablish one or more piles, a, somewhat different procedure is followed, as diagrammatically indicated in Figures 10 to 14, The soil penetrating element t is -connected up as before and it is sunk vertically downwardly by jetting, as before, being shown in Figure 10 to have penetrated the dense soil for a short distance and in Figure 11 to have penetrated the soil to the full extent desired. Naturally the element lll may 'be caused to penetrate to any desired depth within the limits of the apparatus. Initially the jetting fluid, which is usuallyl water under high pressure, escapes to the surface of the rground 'along the outer wall of the casing but later, as the element l0 descends, the earth encircling the upper portion of the velement tends'to back-fill -and to closely engage the outer surface of the casing so that there is an increasing tendency for the wash water toenter the casing through the ports 20h provided .for such entry, as the casing descends, and to pass upwardly through the casing and outwardly through the offtake to the reservoir or pond When the jetting element has descended as far as desired a holding clamp 53 of any suitable type is applied at the ground level to prevent its further downward movement, but the flow of wash water is continued, the action being such that a. considerable cavity is gradually formed by washing, at the lower end of the earth penetrating element IG, as indicated in Figure 12.

.By closely observing the wash water discharged into the pond or basin R and estimating or actually measuring the rate at which solids are being brought to the surface, the size of the cav-ity thus formed by washing during any period of time can be estimated, and the washing action may be halted after this cavity has become as large as thought to be necessary -or desirable. Grout may then be forced downwardly as before, after removal of the inner Apipe 2i, `and caused lto ll the cavity which has been previously washed in the dense soil. A cavity thus .filled with grout is shown in Figure 13. The casing 2U is allowed to remain in the position in `which itis shown in this figure, nafter the grout has been introduced Gil and while vit is hardening. The .grouthose 5l is then 'removed and `a solid casing cap applied, such :as indicated at 54. The vcasing is thusndenitelyanchored toa body Yof artificial stone 55well below the surface. I-n Figure 14 there is;.indi. cated in dotted lines,'at 56, 'an alternative position for the body of grout .and it will be appreciated that the apparatus disclosed Ymay be employed :in-

esta-blishi-ng a grout body close to the surface asv well as one well below the surface.

It vnot infrequently happens that the .soil into which the grout is to be introduced vis of such character that 'no cavity of adequate size, the walls of which are self-sustaining, 4can be established, thus making it'essential to providea means for and 'method of supporting such walls Aduring the period of time following interruption of the flowof water under ,pressure and'before the cavity has been `filled with grout. It has been found that, in numerous instances, collapse of the walls of the cavity resulting inits complete elimination immediately follows `stoppage of the water pump, unless the fluid pressure in the Vcavity is maintained vby the use of other means.

In actual practice I prefer to employ air under pressure as a medium for supporting the walls of the cavity .after the flow of water under pressure .has been cut olf. To `effect this desired result air under desired pressure from pump `l2 is conducted to pipe 2| through conduit I-B and valve 43, simultaneously with or immediately after the closure `of valve 61 Compressed air then issues from the aperture 28 in the tip 'and into the cavity, where it displaces the water, the water being forced through the perforations 20D into the casing 28 and escaping through valve V. After all of the water has been .thus driven #from the cavity and air under pressure begins to escape through offtake conduit -lfl the valve V is closed. Pressure of the air is maintained sufficiently high to insure adequate support to the walls of the cavity.

The water conduit l5 is then disconnected `'from nipple 49 and a connection to the grout pump M established. Valve 443 may then be vclosed and valve 41 'opened so that grout under pressure will be forced downwardly through pipe 2l and caused to loe-discharged into the cavity, the flow of Ygrout under pressure being continued until the cavity has been filled. After 'this pipe `2|, 'lf-member 30, and all associated 'parts are removed from the 'casing :20. The Ycap '50 rmay then be attached to the top of casing 20 and 4grout caused to flow :into the casing until it is completely lled. In this manner the walls of any cavity formed by washing may be fully supported until the cavity is completely filled andobviously the` method may be employed even though the casing be removed after the introduction of the grout instead of being 'allowed to remain in the ground as a pile.,

The method just described has the further, and very substantial, advantage of avoiding the necessity of introducing grout directly into a body of water within a newly .formed cavity, which is'undesirable, and air under pressure may be utilized` to free the cavity of water even where there .is little danger 'of collapse 'of the walls of the 'cavity if unsupported.

By the `use -of suitably placed pressure gauges the air pressure existing in the cavity at any time may be ascertained 'and `if necessary to do so to obviate the need to pump in grout `against an excessive air pressure, `the Apressure may be reduced by allowing air to -escape through valve V Vuntil the desired value is reached. Such a.`

gauge; is. diagrammatic'ally. shown 1in" Figure 2, Abeing indicated at 60. f

be forced downwardly through the smallerinner pipe by connecting a grout supply conduit to the nipple `45 after having'disconnected the compressed air hose from this nipple. When this is done the grout will `issue from the 'discharge' port in the tip of the soil penetrating element'and :more grout will bedeliveredlintov 'the zone below the tip than is the case whenthe outer casing is u's'ed -as the grout conxilu'eting tubefafter removal' of the smaller pipe. lWhen groutin'gwith the aid of the inner pipe 2 I' is'be'ing effected valve V will remain open and offt'akehose lI'l disconnected so that the operatormay-readily perceive any outflow of grout which will, ofcourse, indicate that no more grout can be forced into the earth at that point. The inner pipe may be left in place, if desired, after grouting has'been completed, and thecasing also lllled with; grout to form Aa stronger pile if Ypiling is being'placed, but inthe usual case the inner lpipe is removedbefore the grouthardens, andthe casing suitably capped.y The earth vpenetrating element of the apparatus comprises not only a means for Sinking a shaft in Vibrationless manner, but a means for introducing and withdrawing wash water and air under pressure, va means for forcing grout into a previously prepared zone, and as the metallic shell of a permanent pile. It may be introduced into the earth at various angles so that it can be most conveniently employed in reaching subsoil yzones in and around existingl foundation structures.

Having described the invention, what is claimed as new and desired to be secured by Letters Patent, is:

1; Apparatus of the typedescribed comprising an elongated casing having a tip fixed upon one end, said tip having a fluid discharge channel therein terminating in a fluid discharge port formed in a soil engaging outer surface, and said casing having fluid inlet ports formed in the wall thereof at points remote from the discharge port of the tip, and a pipe or conduit for leading fluid under pressure from a source of supply thru said casing to said channel.

2. Apparatus of the type described comprising an elongated casing having a tip fixed upon one end, said tip having a fluid discharge channel therein terminating in a fluid discharge port formed in a soil engaging outer surfacefa pipe or conduit for leading fluid under pressure froml a source of supply thru said casing to said channel, said casing having fluid inlet ports formed in the wall thereof at points remote from the tip, and means for establishing a sub atmospheric pressure in said casing.

3. Apparatus of the type described comprising in combination, an elongated casing having a tip fixed upon one end provided with a fluid discharge port in an outer surface, said casing having a series of fluid inlet ports formed in that portion thereof which is adjacent the tip said ports being remote from the fluid discharge port of the tip, the remainder being imperforate, and means for supplying fluid under pressure to said pheric pressure in said casing.

tip, to be discharged from the iluididischarge port thereof. f 4. Apparatus of the type described comprising in combinatioman elongated casing having a tip lfixed upon one end provided -with ailuid discharge port in an .outerv sur-facesaid casing having a series of fluid inlet ports formed in that portion thereof which is adjacent; the tip, said ports'being ,remote from the discharge portof the tip, the remainder being imperforate, means for supplying fluid under pressure to said tip to be discharged from the uid'discharge port thereof, and .suction means -forestablishinga sub atmos- 5. Apparatus ofthe -type described comprising, in combination, an elongated casinghavinga tip fixed iupo'n .onefend, said tip having afluid Edischargeportformed in a soil engaging outer surface and the casing having apertures formed in the wall; thereof. remote from the. discharge' port of thetip, a' conduit extendingthru 'the casing togthe tip for leading fluid under pressure tosaid -discharge port, connectionsvbetween said conduit and. sources of liquid and gas under pressure, respectively, and means controlling the ilow of liquid and gas into said conduit from the respective sources. f. z. 1 .i

6.'-The `method `of subsurface. reinforcement vwhich comprises progressively forming an clon-'- gated substantially.r vertical .shaft by' directing :a jetgof fluid .under pressure downwardly against thesoil and advancingthel same downwardly as the soil against which it is directed is displaced, halting the downward movement of the jet after a shaft of predetermined depth has been formed but maintaining the flow of rwash liquid for a further period of time to form a cavity at the lower end of the shaft, and conducting to the surface of the ground the fluid so used for the displacement of soil, together with soil particles carried by said liquid, and thereafter introducing grout into said cavity.

7. The method of treating, in place, a body of porous or permeable subsoil to give it increased bearing strength which comprises, delivering into said body at a chosen distance below the surface a stream of wash fluid, under pressure to Wash .such subsoil and cause its lighter elements to be dislodged, conducting such wash fluid with such disloged elements of subsoil to the surface of the ground, and, after such washing operation has beencompleted, forcing grout into the washed zone.

8. The method set forth in claim 7 in which suction is applied to remove from said body the wash liquid and its contained lighter elements.

9. The method of placing a body of artificial stone or the like below the surface of a body of dense soil which comprises, sinking a shaft Athru said soil by means of a jet of fluid under pressure which is gradually lowered until a shaft of desired depth is formed, the fluid thus discharged, with soil suspended therein, being conducted to the surface, forming at the bottom of said shaft, by continued washing, a chamber for the reception of grout or the like, and thereafter intere rupting the flow of wash water and forcing grout into said cavity. f f

10. The method set forth in claim 9 in which suction is applied to remove from said body of soil the wash liquid and lighter elements of the soil.

11. The method of placing a body of artificial stone or the like below the surface of a body of soil which comprises, forming a cavity in such soil body by discharging water under pressure into @massa 1,1 the sax-ne and conducting the discharged water and soil particles carried thereby to thesurface of: the ground, cutting. oft' the inflowl of wash water after formation ofthe cavity; introducing air" under pressure toa force the Waterv from the same,`v and thereafter' introducing grout.

I3 The method .ot placing a. body of artificial stone or the. like below thesurface of abody of soil which comprised forming a. cavity inA such soil by the usel of a. water jet, conducting the discharged Water and soil particles carried there by fromy the cavity as the washing proceeds, in-

troducing air .under pressureinio the cavity after its"` Iormationto. support the wall, thereof, and introducing groutlwhile maintaining the pressure ofthe air'against the.t walls ofthe cavity;

14. The method of treating in place a body of porous or. permeable subsoil. tok give it increased bearing. strength. which: comprises retrieving from such body the lighter and weaker` elements thereor, and transferringsuch elements to the surface of the ground, by' causing e; currentv of water: to

12 downwardly to said. body, and thereafter through said body and upwardly" to the groimd surface, the upflowing water carrying with it. the said lighter andweaker elements of the: soil, and introducing' grout under pressure mtothe` washed body of subsoil.

1:5.. The method of increasing the bearing strength of abo'dy of subsoil which comprises forming a shaft extending from thev ground: sur- ,faceV down to such body by means of a. down'- Wairdly directed iet'oi fluid. which is lowered Ias thesoilis displaced. until ithas reached the desired elevation, continuouslyremoving the displaced soil, as the ,ietY descends;l to the surface of. the ground maintaining the.- jet afterv its descent; has. been terminated until a substantial body of. soil hasbeen; washed and the lighter and weaker elements thereofremoved to the ground surface,V and. thereafter introducing grout under pressure into'the washedbodyof subsoil to form amatrix for the washedfm-aterial'.

16. The method of formingV a,v body of" artificial stonef or the like below theground level which comprises forming a cavity byA means of a jet of fluid, the displaced soil being floated to the ground level by thev discharged'and upwardly rising fluid, introducing air underf'pressure to support. the otherwise unsupported walls oftheY cavity, and introducing. groutinto said cavity while maintaining the air pressure.

GEORGEy L. DRESSER. 

